Common hardware troubleshooting tools include:
- Network Analysis Module - As shown in Figure 1, a network analysis module (NAM) can be installed in Cisco Catalyst 6500 series switches and Cisco 7600 series routers. NAMs provide a graphical representation of traffic from local and remote switches and routers. The NAM is an embedded browser-based interface that generates reports on the traffic that consumes critical network resources. In addition, the NAM can capture and decode packets and track response times to pinpoint an application problem to the network or the server.
- Digital Multimeters - Digital multimeters (DMMs), such as the Fluke 179 shown in Figure 2, are test instruments that are used to directly measure electrical values of voltage, current, and resistance. In network troubleshooting, most of the multimedia tests involve checking power-supply voltage levels and verifying that network devices are receiving power.
- Cable Testers - Cable testers are specialized, handheld devices designed for testing the various types of data communication cabling. Figure 3 shows two different Fluke cable testers. Cabling testers can be used to detect broken wires, crossed-over wiring, shorted connections, and improperly paired connections. These devices can be inexpensive continuity testers, moderately priced data cabling testers, or expensive time-domain reflectometers (TDRs). TDRs are used to pinpoint the distance to a break in a cable. These devices send signals along the cable and wait for them to be reflected. The time between sending the signal and receiving it back is converted into a distance measurement. The TDR function is normally packaged with data cabling testers. TDRs used to test fiber optic cables are known as optical time-domain reflectometers (OTDRs).
- Cable Analyzers - Cable analyzers, such as the Fluke DTX Cable Analyzer in Figure 4, are multifunctional handheld devices that are used to test and certify copper and fiber cables for different services and standards. The more sophisticated tools include advanced troubleshooting diagnostics that measure distance to performance defect (NEXT, RL), identify corrective actions, and graphically display crosstalk and impedance behavior. Cable analyzers also typically include PC-based software. After field data is collected, the handheld device can upload its data to create up-to-date reports.
- Portable Network Analyzers - Portable devices like the Fluke OptiView in Figure 5 are used for troubleshooting switched networks and VLANs. By plugging the network analyzer in anywhere on the network, a network engineer can see the switch port to which the device is connected, and the average and peak utilization. The analyzer can also be used to discover VLAN configuration, identify top network talkers, analyze network traffic, and view interface details. The device can typically output to a PC that has network monitoring software installed for further analysis and troubleshooting.